Leah Androski and Laura Young
ECB Publishing, Inc.
As gardeners go into planting season, there is an exotic animal to watch for. Be on the lookout for two kinds of hammerhead flatworms – nonnative, invasive species that need to be taken care of immediately after being seen. According to the Florida Fish and Wildlife Conservation Commission (FWC), the “shovel-headed garden flatworm,” Bipalium kewense, often feeds on earthworms (many of which are also nonnative). The “wandering hammerhead worm,” Bipalium vagum, appears to be more of a specialist predator on land mollusks, and so can be a threat – like the New Guinea flatworm – to Florida’s native snails and slugs.
Shovel-headed garden flatworms track their earthworm prey, and once they catch one, they will release a sticky substance containing a neurotoxin. This neurotoxin subdues the earthworm, allowing the hammerhead to strike and squeeze the earthworm to death. Hammerhead worms glide along the ground like snakes and often are mistaken for one. They are known for a dark line down the center of their back and their shovel-shaped head. Their length can reach up to five inches.
If one touches a hammerhead worm, they will release the neurotoxin, which is potentially harmful to the person or animal that touched the worm. Hammerhead worms contain the same toxin that is found in pufferfish. Hammerhead worms are found in humid climates and seem virtually immortal. There are only certain ways that one can get rid of them. If one tries to cut a hammerhead worm, it will regenerate its head, which causes two heads to appear on the hammerhead.
To get rid of the hammerhead worms, one needs to dissolve them in one of these substances: salt, vinegar, citrus oil, boric acid or soap sprays. The first step in getting rid of these worms is to capture them either in a plastic bag or container. To pick up the worm, use gloves or a paper towel to avoid getting any neurotoxins on your skin. After putting the substance in with the worm, allow the hammerhead to dissolve in the solution. After getting rid of the hammerhead worm, treat the container with salt and place it in the freezer for 48 hours. This helps with disinfecting the container. Pesticides can be used to get rid of hammerhead worms, the best option being pyrethrum. One can also use the pesticide in the carbamate or organophosphate family. Be careful if using pesticides, however, because they can be harmful to humans and pets.
There are different ways to prevent hammerhead worms from arriving at your garden. If you have a greenhouse, make sure to do a thorough inspection of all your plants to make sure they do not contain hammerhead worms. If you do happen to stumble upon one, make sure to take a picture before getting rid of it.
FWC says the public can report sightings of nonnative flatworms to IveGot1.org, which helps biologists track distribution of nonnative species. More information about nonnative species can be found at MyFWC.com/Nonnatives.